这道题只要依次按每个桥把坐标对折一下就可以了....



		res = -1;
		memset(delta, -1, sizeof(delta));
		delta[X[0]] = 0;
		for(i = 1; i < n; ++i) {
			int p = X[i] - (int)(sqrt((double)Y[i] * Y[i] - (double)(Y[i] - Y[0]) * (Y[i] - Y[0])) + 1e-12);
			if(p < 0) p = 0;
			for(j = p; j < X[i]; ++j) {
				if(delta[j] == -1) continue;
				j1 = 2 * X[i] - j;
				if(j1 < X[n - 1]) {
					if(delta[j1] == -1 || delta[j] + 1 < delta[j1])
						delta[j1] = delta[j] +  1;
				} else {
					if(res == -1 || delta[j] + 1 < res)
						res = delta[j] + 1;
				}
			}
		}

• Re:ri tnnd (615) rhna 2004-10-18 15:55:35
• Re:ri tnnd (9) uni 2004-10-19 02:33:25